Apparatus for cutting sheets from rolls



(No Model.)

H. FAIRBANKS. I APPARATUs FOR CUTTING SHEETS FROM ROLLS. Patented Apr.30, 18956 Wz'tnesses, Inventar,

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UNITED STATES PATENT OFFIQE.

HENRY FAIRBANKS, OF ST. J OI-INSBURY, VERMONT.

APPARATUS FOR CUTTING SHEETS FROM ROLLS.

SPECIFICATION forming part of Letters Patent No. 538,245, dated April30, 1 895.

Application filed September 21, 1892. fierial No. 446,372. (No model.)

T0 at whom it may concern.-

Be it known that I, HENRY FAIRBANKS, of St. Johnsbury,in the county ofCaledonia and State of Vermont, have invented certain new and usefulImprovements in Apparatus for Cutting Sheets from Rolls, ParticularlySheets of Pulp or Strawboard from the Forming-Roll of the Wet Machine,of which improvements the following description, in connection with theaccompanying drawings, is a full and ex act specification.

The sheets of pulp formed by successive layers wound upon the formingroll have usually been cut, or rather, torn, by the att-endant, drawinga pin under the sheet from one end of the roll to the other.

Most pulp makers have considered it impracticable to use a knife. Thewell known difficulty of cutting a sheet of common paper, when wet, withshears, of which, even with the advantage of meeting edges, the bladesare liable to clog and spring apart, indicates the greater difficulty ofcutting a thick wet sheet when clinging to the roll. It has beenproposed to use a blade springing out from the roll itself, which mighttear its way through, as the pin in the hand of the attendant does, butthis is not cutting. A blade making a shearing cut will not go throughthe thick sheet of fibrous spongy wet paper, but will clog unless thesheet also is moved to strain open a path for it, the crowding upon oneside doing no harm if the other side is drawing away; and on the otherhand a blade merely pressed up to the moving roll, and not having itselfendwise motion will not cut, but will stop the roll or strain themachinery in tearing off the sheet. I have discovered that it isnecessary to give the knife an endwise motion when it strikes the sheet,and that a shearing cut, in combination with the motion of the rollitself is effective. I have accordingly mounted a long flat knife toslide upon a fixed rest with a motion that, while keeping its straightedge parallel to the axis of the roll upon which the pulp sheet isforming, brings that edge to the surface of the roll, and at the sametime carries it endwise in the direction of the length of the roll; andas it is desirable that the knife remain almost in contact with thesurface of the roll after the sheet is out until it is fully detached,namely, .until the roll has made nearly a complete revolution, andshould then be drawn back from that surface to allow the successivelayers of pulp deposited to form the next sheet, and as doing this byhand confines the attendant, I have arranged an automatic device fordrawing it back slowly at first but faster than the pulp accumulatesupon the roll, and to hold it back until a catch is released; and inorder that the knife may deliver a sharp effective stroke, I haveapplied a spring to be strained when the knife is in this way drawnback, and to be held by the said catch until that is released. This maybe released by the attendant, but I have further provided an automaticdevice for pushing back this catch when the pulp sheet attains theproper thick ness, which device, used with certain kinds of pulp,willmake the machine almost independent of the workman, so that it will formand cut sheets of pulp or straw board of uniform thickness and pile themto wait until they can be conveniently folded; and consequently severalmachines can be tended by one man.

In the drawings similar letters of reference designate similar parts inall the figures.

Figure 1 is a plan'view of the forming roll, knife and knife-rest, shownin the plane in which the knife moves, the parts under the restappearing where it is broken away, and by dotted lines. Fig. 2 shows thesliding rod partly flattened into a spring, by which the knife is drawnback after cutting. Fig. 3 illustrates the mechanism under the rest bymeans of which the thickening sheet of pulp upon the roll moves thelever that releases the catch and allows the knife to slide up. Fig. 4is an end view of the formingroll, knife and knife-rest, and Fig. 5 anend view of the knife, knife rest and mechanism by which theaccumulating pulp upon the roll gives motion to the releasing lever.

a is the forming roll, receiving the web of pulp from the couch roll 19,and winding it up into a thick sheet. Thisroll a carries on its extendedgudgeon the coarse screw b, of which screw the thread is not cut as deepas the length of the tooth 0, of the catch, and therefore the point ofthis tooth, after coming to the end of the screw cylinder, rides uponthat end smoothly, all the way round.

0 is the knife, sliding upon the flat top of the rest h, as guided bythe links (1 d which move in arcs about fixed centers. One of these maybe extended to form a handle.

9 is a spring drawing the knife, when re leased, endwise and forwardinto contact with the roll.

e is a rod, under the knife-rest, hinged by a pin (reaching it through aslot in the kniferest), to the link d at r, guided by running through astaple at 'm, which stands down from the under side of the knife-rest,and having the part f flattened into a spring which carries the tooth orcatch 0 at its end in position to be engaged by the screw Z).

i is a lever underneath the rest, moving upon a stud at s projectingdown from said rest, asa fulcrum, and carrying the slide 7c in whichmoves the small roller j in position to be pushed back by the thickeninglayer of pulp upon the roll. The position of this slide is madeadjustable upon the lever?) in order that it may be readily set forsheets of any desired thickness.

The machine of which parts appear in the present drawings is thethree-roll or vacuum wet machine, which has no felt, and of which theforming roll turns over toward the side where the sheets come off, butthe device can be applied to other machines. In this machine the pulp istaken up by the mold-cylinder and couched from that directly to thevacuum roll 19, from which it passes immediately to the under side ofthe forming roll a and the web is wound upon that in successivelayers,building up a thickening sheet. This sheet as it thickens pressesback the roll j and swings the free end Z n of the lever '11 upon itsfulcrum s. This free end engaging the spring f is carried a distanceseveral times the thickness of the forming sheet, and amply sufficient,whether adjusted for thick or thin sheets, to draw back and unhook thetooth 0, and hold it free from the screw 1) while the knife, thusreleased, is drawn by the spring 9 with a swift stroke up to and throughthe sheet of pulp upon the roll, the downward motion of this sheet,combining with the endwise and forward motion of the knife aiding incutting and separating the edges as cut. The sheet cut in this waypasses above the knife and is detached from the roll as it comes over.\Vhen the cut edge below the knife passes down past the rollerj, thatroller is free to swing up against the press roll, and the tension ofthe springf, no longer held back by the point it of the releasing leveri', carries the tooth 0 between the threads of the screw 12, and themotion of that screw begins to draw back the knife; but this motion ofthe knife is at first simply endwise, parallel to the surface of theroll, and for nearly a complete revolution its edge is close enough toscrape off any clinging pulp,

but it begins to draw back in time to give the first layer, going toform the new sheet upon the roll, room to pass without touching thatedge, and the succeeding turns carry the knife back more rapidly. Thetooth or catch 0 follows up between the threads of the screw, and beinglonger than the depth of the groove, slides upon the smooth end of thescrew-cylinder until it is again released.

The curved path of the knife is determined by the swinging links d cl,but it is obvious that substantially the same motion may be given it bycurved guides which may either form part of the knife rest or be carriedby the knife itself, and if carried by the knife may be at its ends, andslide in proper supports extending out from the standards in which theforming roll is mounted, in which case the knife rest may perhaps bedispensed with. What is essential is that the knife approaching the rollshall be at the same time moved endwise, while the sheet to be cut isalso continuously moving at right angles to the plane of the knife. Themovement of the sheet strains the fibers across the cutting edge andwidens the cut as fast as made so as to make room for the advancingblade, while the endwise motion of that blade'prevents the fibersfolding across the edge and clinging to it. This double motion of theknife, and motion of the sheet have not previously been combined, and Ihave proven them to be very effective.

With most kinds of pulp, the edge of the pulp sheet when out clings tothe knife, so that the sheet as it comes over turns completely, andbrings its inside to the top upon the table which stands close behindthe knife rest, this side up being best for folding, and as each iscarried quite over in this way, successive sheets pile quite regularly.

In this apparatus it is evident that certain details may be changedwithout destroying its identity. \Vith a modification of the releasingdevice the spring knife and the carrying screw may be applied to cuttingpaper or sheet metal in desiredlengths from the forming machine. Asshown above, the knife may have sliding guides instead of the swinginglinks. A cam might replace the screw, though hardly with completesuccess, and the releasing device maybe moved by the surface travel ofthe enlarging loaded forming roll instead of by its radial increase.

\Vhen the apparatus is applied to the wet machine, the releasing devicemay be omitted and the catch thrown off by hand, or both this and thescrew, and the knife moved by the handle of the link (I, but the wholemechanisn described above carries out my invention in the best way knownto me; and

I claim- 1. The combination of a forming roll, upon which,in a wetmachine,thick sheets of pulp or straw board are wound, with a straightknife mounted independently of said roll, and

with the mechanism whereby this knife, being parallel with the saidroll, is moved endwise and into contact with it, the whole beingadapted, in cutting a sheet, to combine the motion of approach of theknife, its endwise motion, and the motion of the sheet carried by theroll, whereby the sheet is cut and inverted, substantially as described.

2. The combination of a roll carrying the sheet to be cut, a long knifeparallel with this roll, mechanism supporting and guiding this knife anda spring so connected as to draw it endwise in its swing toward theroll, substantially as herein set forth.

3. The combination of a roll, carrying the sheet to be cut, a long knifesupported for moving into light contact with this roll, a spring actingto draw it endwise in its motion toward the roll, a connecting rod andcatch attached to draw it in the other direction and acoarse screwcarried by the roll and engaging this catch, adapted to move it andthereby the knife against the strain of the said spring,- substantiallyas herein set forth.

4. The combination of a roll carrying the sheet to be cut, a straightknife supported and guided into light contact with this roll, 'a springacting to draw it endwise and toward the roll, mechanism connected todraw the said knife in the other direction, a catch holding it with thesaid spring strained, and a releasing lever adapted to push back thiscatch when moved by the thickening sheet upon the roll, substantially asand for the purpose specified.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, on this 19th day of September, A.D. 1892.

HENRY FAIRBANKS.

Witnesses:

O. M. SPENCER, WM. 0. TYLER.

